FizzBuzz question in R language.

26. > fizzbuzz <- function(n) {
# Write your code here
}
> fizzbuzz(20)
[1] "1" "2" "Fizz"
[4] "4" "Buzz" "Fizz"
[7] "7" "8" "Fizz"
[10] "Buzz" "11" "Fizz"
[13] "13" "14" "FizzBuzz"
[16] "16" "17" "Fizz"
[19] "19" "Buzz"

28. fb1 <- function(n) {
fb <- character(n)
for (i in 1:n) {
if (i %% 3 == 0 && i %% 5 == 0)
fb[i] <- "FizzBuzz"
else if (i %% 3 == 0)
fb[i] <- "Fizz"
else if (i %% 5 == 0)
fb[i] <- "Buzz"
else
fb[i] <- i
}
fb
}

30. fb2 <- function(n) {
sapply(1:n, function(i) {
if (i %% 3 == 0 && i %% 5 == 0)
"FizzBuzz"
else if (i %% 3 == 0)
"Fizz"
else if (i %% 5 == 0)
"Buzz"
else
i
})
}

35. fb3 <- function(n) {
isFizz <- rep(c(F,F,T), length=n)
isBuzz <- rep(c(F,F,F,F,T), length=n)
isNumber <- !isFizz & !isBuzz
fizz <- ifelse(isFizz, "Fizz", "")
buzz <- ifelse(isBuzz, "Buzz", "")
number <- ifelse(isNumber, 1:n, "")
paste(fizz, buzz, number, sep="")
}

40. > N <- 100
> benchmark(fb1(N), fb2(N), fb3(N),
order="relative",
replications=10000)
test elapsed relative
3 fb3(N) 4.172 1.000000
2 fb2(N) 6.669 1.598514
1 fb1(N) 7.779 1.864573

41. > N <- 10000
> benchmark(fb1(N), fb2(N), fb3(N),
order="relative",
replications=100)
test elapsed relative
3 fb3(N) 2.907 1.000000
2 fb2(N) 7.823 2.691090
1 fb1(N) 8.200 2.820777

42. > N <- 1000000
> benchmark(fb1(N), fb2(N), fb3(N),
order="relative",
replications=5)
test elapsed relative
3 fb3(N) 28.287 1.000000
1 fb1(N) 46.198 1.633188
2 fb2(N) 52.223 1.846184

47. library(compiler) # Installed by default
library(inline) # Needs manual installation
fbcpp <- cxxfunction(
signature(ns="integer"),
body=src, # Shown in the next slide
plugin="Rcpp")
fb1.c <- cmpfun(fb1)
fb2.c <- cmpfun(fb2)
fb3.c <- cmpfun(fb3)
fbcpp.c <- cmpfun(fbcpp)

48. int n = Rcpp::as<int>(ns);
Rcpp::CharacterVector fb(n);
for (int index = 0; index < n; index++) {
int i = index + 1;
if (i % 3 == 0 && i % 5 == 0)
fb[index] = "FizzBuzz";
else if (i % 3 == 0)
fb[index] = "Fizz";
else if (i % 5 == 0)
fb[index] = "Buzz";
else {
char s[11]; // Integer is 10 or less digit
sprintf(s, "%d", i);
fb[index] = s;
}
}
return(fb);